Pawl-and-ratchet mechanism



Feb. 26 1924. 1, 85,217.

G. F. cRAss PAWL AND RATCHET MECHANISM Filed May v 4, 1922 6' 5 rye E (910529 Patented Feb. 26, 1924.

GEORGE F. GRASS, or ITHACA, NEW YORK, ASSIGNOR or ONE-HALF 'IO OHN H.

McCOR-MICK, or ITHACA, NEW YoaK.

i PAWL-AND-RATGHET MECHANISM.

Application filed May 4, 1922. Serial No. 558,450.

To all whom it may concern:

Be it known that I, GEORGE F. GRASS, a citizen of the United States of America, residing at Ithaca, in the county of Tompkins and State of New York, have invented certain new and useful Improvements in Pawland-Ratchet Mechanisms, of which the following is a specification.

This invention relates to certain new and useful improvements in pawl and ratchet mechanisms or automatic one-way clutch devices employed in various machinery andupon shade rollers for efiecting the simultaneous rotation of two elements in one direction while permitting relative rotation of the elements in the opposite direction.

An object of the invention is to provide a simple construction that will be inexpensive to manufacture and will also be very eflicient and durable in operation.

Another object of the invention is to provide a device of the class mentioned which may be readily assembled or disassembled and the parts of which are normally so secured together as to retain their position permanently during use.

A further objectv of the invention is to provide a device of the class mentioned, the pawl elements of which are so associated with the rotatable member carrying the same that said pawl elements will be retained in operative position upon the other rotatable member being removed so that accidental displacement of the pawl elements from their operative position is prevented and the assembling of the device made more easy.

With the above general objects in view, and others that will appear as the nature of the invention is better understood, the same consists in the novel construction, combination and arrangement of parts hereinafter more fully described, illustrated in the accompanying drawings, and pointed out in the appended claims.

In the drawings:

Figure 1 is a view partly in side elevation and partly in central section of one form of ratchet mechanism constructed in accordance with the present invention.

Figure 2 is a fragmentary view looking towards the right of Figure 1 with the removable cover plate removed, and

Figure 3 is an elevational view of the pawl member as shown in Figure 2.

' Referring to the form of the invention illustrated in Figures -1 and 2, the device embodies a pair of rotary or relatively rotatable members 5 and 6 disposed in concentric relation or one within the other, the member 5 being of ring shape and the member 6 being arranged to snugly fit within the central opening of the member 5 with its ratchet teeth 7 carried by the member 5 contacting the outer periphery of said mem ber 6 as shown clearly in Figure 2. The ratchet teeth 7 are preferably formed as shown in Figure 2 with cam shaped surfaces 9 adapted to cooperate with pawl elements 10 carried by the member 6. Thesepawl elements are of areuate form and constitute more than a semi-circle as do also the recesses 11 provided in the outer surface of the member 6 to snugly receive the pawl elements 10. The pawl elements 10 have a'con caved inner face and are of such size as to normally have one end portion projecting outwardly beyond the outer surface ofthe member 6 when the other end is flush with said surface. As the pawl elements 10 and the recesses 11 are of more than semi-circular form, the pawl elements can only be inserted in or removed from said recesses in a lateral direction and the pawls will not accidentally fall out of the recesses when the inner member 6 is removed for repairs or prior to the insertion of said inner member 6 after the pawls have been placed in the recesses 11 during the initial assembling of the device. As shown in Figure 2..the pawls 10 are provided in lesser number than the ratchet teeth 7 so that one pawlis always disposed to be engaged by' an adjacent ratchet tooth for preventing rotation of the member 6 relative to the member 5 in one direction, although said members may relatively rotate freely at all times in the opposite direction.

The member 5 is preferably closed at one side by an integral disk portion 12, and the opposite side of the member 5 may be closed by a removable disk or cover plate 13 bolted as at 14 to the member 5 so as to retain the pawl elements 10 in the recesses 11 or against lateral displacement out of said recesses. In the construction shown, in Figures 1 and 2 the member 6 is shown keyed upon a drive shaft 15 so that when said shaft is driven in one direction the member 5 will be caused to rotate therewith while if the shaft 15 is held stationary the member 5 may continue to rotate in such direction although prevented from rotation in the opposite direction.

The recesses and pawl elements of the present invention may accordingly be described as substantially three-fourths moon shape in elevation with the pawl elements of greater size than the recesses so that the ends of the pawl will project beyond the adjacent surface of the member carrying the same for cooperation with the ratchet teeth of the adjacent rotatable member.

In Figure 2 the pawl element 10 is shown as provided with an anti-friction member 16 at its inoperative end so that friction is greatly reduced and the riding of the pawl 10 over the cam surfaces 9 of said teeth 7 is made more easy. As shown in Figure 3 the anti-friction element 16 preferably consists of a roller which is journaled upon a transverse pin 17 fixed in a pair of spaced ears 18 which are formed by slotting this end of the pawl element as at 19.

From the foregoing, it will be seen that the essential feature of this mechanism is that the pawl element must be of circular form or of a form to include more than a semi-circle and fitting within corresponding recesses so that one end of the pawl will project beyond the adjacent surface of the member carrying the same when the other end of said pawl is flush with said surface, thus insuring operative relation between said pawl and the ratchet teeth and presenting a structure wherein removal or positioning of the pawl elements can only be had by moving such elements in a lateral direction.

From the foregoing it will be evident that I have provided a very simple ratchet mechanism or one way automatic clutch which may be manufactured at a very low cost and, particularly, one which may be assembled in great quantities by the employment of unskilled labor, this being particularly true in view of the fact that when the pawls 10 are once placed in their recesses the same will not accidentally drop out of the same when confined against lateral movement. In this way the accidental loss or dropping of the pawls, before assemblage of the members 5 and 6, is prevented and a very durable and etlicient construction is had. Also, the particular form of the device will lend itself to modern manufacturing methods and it will also be seen that the'parts when assembled, are thoroughly secured and the moving parts will present a minimum amount of friction.

,Vhile the form of the invention herein shown and described is what is believed to be the prei'ierred embmliment thereof, it is nevertheless to be understood that various forms, modifications and arrangen'ients of the parts may be made without departing from the spirit and scope of the invention as claimed.

hat I claim is new is:

1. In a pawl and ratchet mechanism, the combination with ratchet teeth each having an operative and a neutral side, of a pawl operatively associated with said teeth, and an anti-friction member journaled in said pawl adapted for engaging the neutral sides of said ratchet teeth for permitting easy riding movement of the pawl thereover during operation of said mechanism.

2. In a pawl and ratchet mechanism, the combination with ratchet teeth each having an operative and a neutral side, of a pawl of more than half moon shape operatively associated with said teeth, said pawl having its inoperative end slotted, and an anti-friction member carried by said slotted end adopted for engaging the neutral sides of said ratchet teeth for permitting easy riding movement of the pawl thereover during operation of said mechanism.

3. In a pawl and ratchet mechanism, the combination with ratchet teeth each havin an operative and a neutral side, of a pawl of more than half moon shape operatively associated with said teeth, said pawl having one of its ends slotted to form a pair of spaced ears, and a roller journaled between said ears'adapted for engaging the neutral sides of said ratchet teeth for permitting easy riding movement of the pawl thereover during operation of said mechanism.

Intestimony whereof I atlix my signature.

GEORGE F. GRASS. 

